18 resultados para conservation.
em Consorci de Serveis Universitaris de Catalunya (CSUC), Spain
Resumo:
Satellite remote sensing imagery is used for forestry, conservation and environmental applications, but insufficient spatial resolution, and, in particular, unavailability of images at the precise timing required for a given application, often prevent achieving a fully operational stage. Airborne remote sensing has the advantage of custom-tuned sensors, resolution and timing, but its price prevents using it as a routine technique for the mentioned fields. Some Unmanned Aerial Vehicles might provide a “third way” solution as low-cost techniques for acquiring remotely sensed information, under close control of the end-user, albeit at the expense of lower quality instrumentation and instability. This report evaluates a light remote sensing system based on a remotely-controlled mini-UAV (ATMOS-3) equipped with a color infra-red camera (VEGCAM-1) designed and operated by CATUAV. We conducted a testing mission over a Mediterranean landscape dominated by an evergreen woodland of Aleppo pine (Pinus halepensis) and (Holm) oak (Quercus ilex) in the Montseny National Park (Catalonia, NE Spain). We took advantage of state-of-the-art ortho-rectified digital aerial imagery (acquired by the Institut Cartogràfic de Catalunya over the area during the previous year) and used it as quality reference. In particular, we paid attention to: 1) Operationality of flight and image acquisition according to a previously defined plan; 2) Radiometric and geometric quality of the images; and 3) Operational use of the images in the context of applications. We conclude that the system has achieved an operational stage regarding flight activities, although with meteorological limits set by wind speed and turbulence. Appropriate landing areas can be sometimes limiting also, but the system is able to land on small and relatively rough terrains such as patches of grassland or short matorral, and we have operated the UAV as far as 7 km from the control unit. Radiometric quality is sufficient for interactive analysis, but probably insufficient for automated processing. A forthcoming camera is supposed to greatly improve radiometric quality and consistency. Conventional GPS positioning through time synchronization provides coarse orientation of the images, with no roll information.
Resumo:
We present a new a-priori estimate for discrete coagulation fragmentation systems with size-dependent diffusion within a bounded, regular domain confined by homogeneous Neumann boundary conditions. Following from a duality argument, this a-priori estimate provides a global L2 bound on the mass density and was previously used, for instance, in the context of reaction-diffusion equations. In this paper we demonstrate two lines of applications for such an estimate: On the one hand, it enables to simplify parts of the known existence theory and allows to show existence of solutions for generalised models involving collision-induced, quadratic fragmentation terms for which the previous existence theory seems difficult to apply. On the other hand and most prominently, it proves mass conservation (and thus the absence of gelation) for almost all the coagulation coefficients for which mass conservation is known to hold true in the space homogeneous case.
Resumo:
The field of laser application to the restoration and cleaning of cultural assets is amongst the most thriving developments of recent times. Ablative laser technological systems are able to clean and protect inestimable works of art subject to atmospheric agents and degradation over time. This new technology, which has been developing for the last forty year, is now available to restorers and has received a significant success all over Europe. An important contribution in the process of laser innovation has been carried out in Florence by local actors belonging to a creative cluster. The objects of the analysis are the genesis of this innovation in this local Florentine context, and the relationships among the main actors who have contributed in it. The study investigates how culture can play a part in the generation of ideas and innovations, and which are the creative environments that can favour it. In this context, the issue of laser technologies for the restoration of cultural heritage has been analysed as a case study in the various paths taken by the Creative Capacity of the Culture (CCC).
Resumo:
We show that if performance measures in a stochastic scheduling problem satisfy a set of so-called partial conservation laws (PCL), which extend previously studied generalized conservation laws (GCL), then the problem is solved optimally by a priority-index policy for an appropriate range of linear performance objectives, where the optimal indices are computed by a one-pass adaptive-greedy algorithm, based on Klimov's. We further apply this framework to investigate the indexability property of restless bandits introduced by Whittle, obtaining the following results: (1) we identify a class of restless bandits (PCL-indexable) which are indexable; membership in this class is tested through a single run of the adaptive-greedy algorithm, which also computes the Whittle indices when the test is positive; this provides a tractable sufficient condition for indexability; (2) we further indentify the class of GCL-indexable bandits, which includes classical bandits, having the property that they are indexable under any linear reward objective. The analysis is based on the so-called achievable region method, as the results follow fromnew linear programming formulations for the problems investigated.
Resumo:
Historical exploitation of the Mediterranean Sea and the absence of rigorous baselines makes it difficult to evaluate the current health of the marine ecosystems and the efficacy of conservation actions at the ecosystem level. Here we establish the first current baseline and gradient of ecosystem structure of nearshore rocky reefs at the Mediterranean scale. We conducted underwater surveys in 14 marine protected areas and 18 open access sites across the Mediterranean, and across a 31-fold range of fish biomass (from 3.8 to 118 g m22). Our data showed remarkable variation in the structure of rocky reef ecosystems. Multivariate analysis showed three alternative community states: (1) large fish biomass and reefs dominated by non-canopy algae, (2) lower fish biomass but abundant native algal canopies and suspension feeders, and (3) low fish biomass and extensive barrens, with areas covered by turf algae. Our results suggest that the healthiest shallow rocky reef ecosystems in the Mediterranean have both large fish and algal biomass. Protection level and primary production were the only variables significantly correlated to community biomass structure. Fish biomass was significantly larger in well-enforced no-take marine reserves, but there were no significant differences between multi-use marine protected areas (which allow some fishing) and open access areas at the regional scale. The gradients reported here represent a trajectory of degradation that can be used to assess the health of any similar habitat in the Mediterranean, and to evaluate the efficacy of marine protected areas.
Resumo:
En el presente artículo se revisan las limitaciones de aplicación del método del Número de Curva del Soil Conservation Service, modelo conceptual ampliamente difundido para el cálculo de la escorrentía originada por una tormenta. Si bien es cierto que el método posee una serie de capacidades y ventajas que han motivado su éxito en la modelación hidrológica, en particular su simplicidad de uso y la economía en la obtención de los datos físicos necesarios, no es menos cierto que deben contemplarse una serie de restricciones de aplicación. La amplia difusión de la que ha sido objeto ha propiciado la discusión y revisión crítica del modelo, acotando paulatinamente sus límites. Entre los más significativos de éstos, destacan la necesidad de regionalizar, a partir de campañas de aforos, ciertas hipótesis y parámetros del método, así como las precauciones que deben adoptarse si se aplica a cuencas forestales densas con suelos muy permeables.
Resumo:
En el presente estudio hacemos una revisión del estado de conservación y las tendencias poblacionales de la codorniz común (Coturnix coturnix) desde 1900 hasta nuestros días. Algunos de los datos de los que disponemos son contradictorios con respecto al estado de la especie, que presenta ciertas características que dificultan el poder proporcionar estimas poblacionales fiables. Datos recientes sugieren claramente, tanto a escala local como a escala transnacional, que las poblaciones atlánticas de codorniz común han permanecido estables en las dos últimas décadas y que la práctica de liberar codornices criadas en granjas (híbridas con la codorniz japonesa, Coturnix japonica) con finalidades cinegéticas, no afectan significativamente a nuestras estimas. Por otra parte, los complejos patrones de desplazamiento de esta especie requieren especial atención. En este sentido, el análisis de recuperaciones de anillas puede aportar información relevante, especialmente de los movimientos nomádicos de codornices a la búsqueda de hábitats adecuados, tras la destrucción de los cultivos invernales de cereales debido a la siega. Así, al desarrollar un modelo de distribución de cría para esta especie, se debe incorporar continuamente información actualizada de los cambios estacionales de hábitat y clima, con el fin de obtener unas predicciones óptimas. En este sentido, por ejemplo, la inclusión de datos quincenales de índices de vegetación en los modelos de distribución ha dado muy buenos resultados. La obtención de predicciones fiables de los cambios de la distribución de la especie y de sus desplazamientos durante la estación de cría puede ser muy útil para un mejor conocimiento del estado de conservación y las tendencias poblacionales de la especie, así como para el diseño de futuras medidas de gestión.
Resumo:
We present a dual-trap optical tweezers setup which directly measures forces using linear momentum conservation. The setup uses a counter-propagating geometry, which allows momentum measurement on each beam separately. The experimental advantages of this setup include low drift due to all-optical manipulation, and a robust calibration (independent of the features of the trapped object or buffer medium) due to the force measurement method. Although this design does not attain the high-resolution of some co-propagating setups, we show that it can be used to perform different single molecule measurements: fluctuation-based molecular stiffness characterization at different forces and hopping experiments on molecular hairpins. Remarkably, in our setup it is possible to manipulate very short tethers (such as molecular hairpins with short handles) down to the limit where beads are almost in contact. The setup is used to illustrate a novel method for measuring the stiffness of optical traps and tethers on the basis of equilibrium force fluctuations, i.e., without the need of measuring the force vs molecular extension curve. This method is of general interest for dual trap optical tweezers setups and can be extended to setups which do not directly measure forces.
Resumo:
The adequate selection of indicator groups of biodiversity is an important aspect of the systematic conservation planning. However, these assessments differ in the spatial scale, in the methods used and in the groups considered to accomplish this task, which generally produces contradictory results. The quantification of the spatial congruence between species richness and complementarity among different taxonomic groups is a fundamental step to identify potential indicator groups. Using a constructive approach, the main purposes of this study were to evaluate the performance and efficiency of eight potential indicator groups representing amphibian diversity in the Brazilian Atlantic Forest. Data on the geographic range of amphibian species that occur in the Brazilian Atlantic Forest was overlapped to the full geographic extent of the biome, which was divided into a regular equal-area grid. Optimization routines based on the concept of complementarily were applied to verify the performance of each indicator group selected in relation to the representativeness of the amphibians in the Brazilian Atlantic Forest as a whole, which were solved by the algorithm"simulated annealing", through the use of the software MARXAN. Some indicator groups were substantially more effective than others in regards to the representation of the taxonomic groups assessed, which was confirmed by the high significance of data (F = 312.76; p < 0.01). Leiuperidae was considered as the best indicator group among the families analyzed, as it showed a good performance, representing 71% of amphibian species in the Brazilian Atlantic Forest (i.e. 290 species), which may be associated with the diffuse geographic distribution of its species. This study promotes understanding of how the diversity standards of amphibians can be informative for systematic conservation planning on a regional scale.
Resumo:
Międzyrzecz Fortified Front, were Natura 2000 site PLH080003 Nietoperek is situated, was built by the Germans in the 1930s and during the World War II. It is composed of above ground bunkers connected by underground tunnels of ca. 32 km total length. Nietoperek is the eighth largest bats hibernation site in EU. Monthly censuses were carried out from October to April during three consecutive winter seasons (2011/12 – 2013/14) in area covering ca. 30% of the undergrounds. The aims of the study were: (1) to describe changes in numbers of each species in the course of hibernation season, (2) to suggest deadlines for counting particular bat species to obtain maximal numbers and (3) to describe negative impact of tourism on hibernating bats. The results will be useful for restriction of winter tourism in Nietoperek. The total number of bats observed during the study was 37869 individuals of 9 species. Because of difficulties in distinguishing without handling M. mystacinus and M. brandtii were treated as one group. M. myotis constituted from 53% (first season) to 64% (last season) of all hibernating bats. The maximal numbers of individuals were observed in November (first two seasons) and in December (third season). M. daubentonii constituted from 27% (first season) to 21% (last season) and M. nattereri from 10% (first season) to 11% (second season) of all bats. During the three seasons the maximal numbers of M. daubentonii and M. nattereri were observed in November and December respectively. B. barbastellus and P. auritus constituted from 4% (first season) to 2% (last season) of the multi species colony. The maximal numbers of B. barbastellus were observed in January and P. auritus in January (first and second seasons) and in December (third season). Results indicated that the best period for counting maximal numbers of M. myotis and M. daubentonii is November, for M. nattereri is December and for B. barbastellus and P. auritus is January. The study undertaken in the part visited by tourists in winter (total length of 900 m) proved negative effect caused by human disturbance with 23% decline of total bat numbers.
Resumo:
Freshwater species worldwide are experiencing dramatic declines partly attributable to ongoing climate change. It is expected that the future effects of climate change could be particularly severe in mediterranean climate (med-) regions, which host many endemic species already under great stress from the high level of human development. In this article, we review the climate and climate-induced changes in streams of med-regions and the responses of stream biota, focusing on both observed and anticipated ecological responses. We also discuss current knowledge gaps and conservation challenges. Expected climate alterations have already been observed in the last decades, and include: increased annual average air temperatures; decreased annual average precipitation; hydrologic alterations; and an increase in frequency, intensity and duration of extreme events, such as floods, droughts and fires. Recent observations, which are concordant with forecasts built, show stream biota of med-regions when facing climate changes tend to be displaced towards higher elevations and upper latitudes, communities tend to change their composition and homogenize, while some life-history traits seem to provide biota with resilience and resistance to adapt to the new conditions (as being short-lived, small, and resistant to low streamflow and desiccation). Nevertheless, such responses may be insufficient to cope with current and future environmental changes. Accurate forecasts of biotic changes and possible adaptations are difficult to obtain in med-regions mainly because of the difficulty of distinguishing disturbances due to natural variability from the effects of climate change, particularly regarding hydrology. Long-term studies are needed to disentangle such variability and improve knowledge regarding the ecological responses and the detection of early warning signals to climate change. Investments should focus on taxa beyond fish and macroinvertebrates, and in covering the less studied regions of Chile and South Africa. Scientists, policy makers and water managers must be involved in the climate change dialogue because the freshwater conservation concerns are huge.
Resumo:
In Chile, mediterranean climate conditions only occur in the Central Zone (ChMZ). Despite its small area, this mediterranean climate region (med-region) has been recognised as a hotspot for biodiversity. However, in contrast to the rivers of other med-regions, the rivers in the ChMZ have been studied infrequently, and knowledge of their freshwater biodiversity is scarce and fragmented. We gathered information on the freshwater biodiversity of ChMZ, and present a review of the current knowledge of the principal floral and faunal groups. Existing knowledge indicates that the ChMZ has high levels of endemism, with many primitive species being of Gondwanan origin. Although detailed information is available on most floral groups, most faunal groups remain poorly known. In addition, numerous rivers in the ChMZ remain completely unexplored. Taxonomic specialists are scarce, and the information available on freshwater biodiversity has resulted from studies with objectives that did not directly address biodiversity issues. Research funding in this med-region has a strong applied character and is not focused on the knowledge of natural systems and their biodiversity. Species conservation policies are urgently required in this highly diverse med-region, which is also the most severely impacted and most populated region of the country.
Resumo:
Brown trout is a cold-adapted freshwater species with restricted distribution to headwater streams in rivers of the South European peninsulas, where populations are highly vulnerable because Mediterranean regions are highly sensitive to the global climatic warming. Moreover, these populations are endangered due to the introgressive hybridization with cultured stocks. Individuals from six remnant populations in Western Mediterranean rivers were sequenced for the complete mitochondrial DNA control region and genotyped for 11 nuclear markers. Three different brown trout lineages were present in the studied region. Significant genetic divergence was observed among locations and a strong effect of genetic drift was suggested. An important stocking impact (close to 25%) was detected in the zone. Significant correlations between mitochondrial-based rates of hatchery introgression and water flow variation suggested a higher impact of stocked females in unstable habitats. In spite of hatchery introgression, all populations remained highly differentiated, suggesting that native genetic resources are still abundant. However, climatic predictions indicated that suitable habitats for the species in these rivers will be reduced and hence trout populations are highly endangered and vulnerable. Thus, management policies should take into account these predictions to design upstream refuge areas to protect remnant native trout in the region
Resumo:
Seabirds are facing a growing number of threats in both terrestrial and marine habitats, and many populations have experienced dramatic changes over past decades. Years of seabird research have improved our understanding of seabird populations and provided a broader understanding of marine ecological processes. In an effort to encourage future research and guide seabird conservation science, seabird researchers from 9 nations identified the 20 highest priority research questions and organized these into 6 general categories: (1) population dynamics, (2) spatial ecology, (3) tropho-dynamics, (4) fisheries interactions, (5) response to global change, and (6) management of anthropogenic impacts (focusing on invasive species, contaminants and protected areas). For each category, we provide an assessment of the current approaches, challenges and future directions. While this is not an exhaustive list of all research needed to address the myriad conservation challenges seabirds face, the results of this effort represent an important synthesis of current expert opinion across sub-disciplines within seabird ecology. As this synthesis highlights, research, in conjunction with direct management, education, and community engagement, can play an important role in facilitating the conservation and management of seabird populations and of the ocean ecosystems on which they and we depend.
Resumo:
We have pragmatic and ethical obligations to conserve rivers and their biodiversity. This chapter outlines how and why river conservation is important. To make a difference, we must act as individuals and groups, using water wisely and protecting vulnerable assets such as water quality, riparian zones and aquatic biodiversity